GB1010252A - Copolymers - Google Patents

Abstract

A solid copolymer has repeating units consisting essentially of (a) -OCH2-groups interrupted with (b) <FORM:1010252/C3/1> in which R, which may be the same or different, is hydrogen, or an alkyl or haloalkyl radical of one to six carbon atoms, X is methylene, methylene ether or methylene thioether and n is 0, 1, 2 or 3, the ratio of (b)/(a) being 0 to 100/100. The copolymers may be produced by polymers, formaldehyde or trioxane with a cyclic thioether, thioacetal, dithio ketal or thioketal. Specified compounds are ethylene,-propylene or butylene sulphide, tetrahydrothiophene, 1 - 3 - oxythiolane, 2 - methyl 1 - 3 - oxythiolane, 1 - 3 - dithiolane, and 2-methyl - 1 - 3 - dithiolane. Cationically active catalysts, e.g. Lewis acids, may be present. An inert liquid media may or may not be present. A third comonomer, e.g. ethylene oxide, propylene oxide, 1-3-dioxolane and diethylene glycol formal may also be present.ALSO:1,3 - Oxothiolane and 2-methyl-1,3-oxothiolane may be prepared by the reaction of a mercaptoethanol with an aldehyde or an aldehyde-yielding compound, in the presence of an acid. In an example, 1 : 3-oxothiolane is prepared by heating 390 parts mercaptoethanol and 153 parts paraformaldehyde in the presence of 0.05 to 0.5% of a strong acid, 200 parts by volume of benzene added and the water of reaction distilled off azeotropically; the solvent is removed and the residue distilled under normal pressure or in vacuo either after the addition of a further 0.2 to 0.5% acid or after neutralization of the acid present. The yield is 9%. The product may be purified with potassium or aluminium hydroxide and dried over metallic sodium.